Mortality Analysis for the period 2003 to 2014

HIV Mortality Analysis


In order to explore HIV Mortality in Puerto Rico, we conducted a crude analysis using the data from the HIV Surveillance System for 2003 to 2014. The trend in HIV mortality can be seeing in figure 1:

graphic 1.
Figure 1 shows the crude HIV mortality trend in Puerto Rico for the period 2003-2014. This preliminar analysis shows a decreasing HIV trend of 4.6% (10.0% in 2003 compared with 5.6% in 2014) in Puerto Rico. In figure 2 we stratified by mode of transmission (Men who have Sex with Men, Injection Drugs Users and Heterosexual Contact):


graphic 2

Figure 2 also shows a decreasing trend in HIV in Puerto Rico. In the IDU group, we can see a decrease of almost 7% which might explain the reason why the overall mortality is also decreasing.


Comparing deaths of Men who have Sex with Men (MSM) and Injected Drugs Users (IDU)

In order to compare deaths among MSM and IDU, we calculate the absolute difference between years (according to the CDC mathematical model) and verify whether there was a significant difference between these groups. The raw file can be accessed here.

The structure of the data is as follows:

##           year 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014
## type case                                                            
## msm  yes         14   12    3    6    2    4   21   11   23   16    1
##      no          91  105   93   90   84   86   90   69   80   57   73
## idu  yes         17   66   64   72   20   39   38    7   57   17   36
##      no         405  388  454  390  318  338  299  261  268  211  194


The absolute differences of MSM and IDU cases for 2004-2014 are:

## 
## ------------------
##  year   MSM   IDU 
## ------ ----- -----
##  2004  0.154 0.042
## 
##  2005  0.114 0.17 
## 
##  2006  0.032 0.141
## 
##  2007  0.067 0.185
## 
##  2008  0.024 0.063
## 
##  2009  0.047 0.115
## 
##  2010  0.233 0.127
## 
##  2011  0.159 0.027
## 
##  2012  0.288 0.213
## 
##  2013  0.281 0.081
## 
##  2014  0.014 0.186
## ------------------



To perform the analysis we used a Poisson model to compare the proportions between MSM and IDU. Figure 3 show the crude model.

graphic 3

In order to validate the model, we need to evaluate interaction in the predictor variables. Figure 4 show a significance in the likelihood-ratio test (p-value < 0.00001).

graphic 4

Table 1 show the respective p-values obtained in the Poisson model for the specific years:

Year p_value
2004 < 0.0001
2005 0.205
2006 0.013
2007 0.017
2008 0.190
2009 0.084
2010 0.025
2011 < 0.0001
2012 0.222
2013 < 0.0001
2014 0.010

We can see that for years 2005, 2008, 2009 and 2012 the results were not statistically significant (0.205, 0.190, 0.084, 0.222 respectively).

JoinPoint Software

We used JoinPoint Software to verify if there were significant differences in the absolute differences calculated using the CDC mathematical model across the period of study. We ran the analysis for both MSM and IDU groups. Figure 5 show no significant annual percent change for the group MSM.
graphic 5

Likewise, there was no statistical difference in the annual percent change for the IDU group.

graphic 6

Further investigation will be needed in order to have a better insight of the behavior of HIV mortality in Puerto Rico.